New Synthetic Approach to 1,2-thiodisacharides from 3-nitro-and 3-cyano enones

CASSETT, C., WITCZAK, Z. J., SPANEVELLO, R. A., MANGIONE, M. I. SUAREZ, A. G.

Chicago, EE.UU

Congreso; 233º American Chemical Society National Meeting,; 2007

American Chemical Society

As a part of a program to develop novel, versatile methods and strategies for S-thiodisaccharide synthesis, we have recently reported the synthesis and evaluation of differently functionalized S-1, 4- thiodisacharides and their sulfones. Here we describe further assessment of the stereoselective Michael addition of reactive 1-thiosugar 2 to functionalized carbohydrate enones with EWG groups at C-3, -NO2, and -CN, 1 and 5 respectively. In accordance with this new stereoselective concept, the synthesis of first novel 1, 2-thidisacharides is achieved. The high reactivity of nitro enone 1 is quite evident as the reaction is completed in 1h in comparison to much longer time 10h of the reaction in the case of the enone 5. We demonstrated that activation of the conjugate Michael addition with various bases such as Et3N, and TMG allows the stereoselective synthesis of S-1, 2- linked thiodisaccharides with no protecting group manipulation during and after functionalization. Subsequent reduction of the -NO2 and –CN group with NaBH4/CoCl2 complex produce 1,2-thioaminodisaacharides 4 and 7 as first representative of new family of 1,2-á-linked thioaminodisaccharides. The scope and limitation of this novel approach will be reported in details.2, and -CN, 1 and 5 respectively. In accordance with this new stereoselective concept, the synthesis of first novel 1, 2-thidisacharides is achieved. The high reactivity of nitro enone 1 is quite evident as the reaction is completed in 1h in comparison to much longer time 10h of the reaction in the case of the enone 5. We demonstrated that activation of the conjugate Michael addition with various bases such as Et3N, and TMG allows the stereoselective synthesis of S-1, 2- linked thiodisaccharides with no protecting group manipulation during and after functionalization. Subsequent reduction of the -NO2 and –CN group with NaBH4/CoCl2 complex produce 1,2-thioaminodisaacharides 4 and 7 as first representative of new family of 1,2-á-linked thioaminodisaccharides. The scope and limitation of this novel approach will be reported in details.